Roadside object recognition apparatus

ABSTRACT

A roadside object recognition apparatus recognizes a roadside object that is present on a travel route on which an own vehicle travels. The roadside object is used for driving control of the vehicle. In the roadside object recognition apparatus, a reflection point acquiring unit acquires, using a radar that emits electromagnetic waves, a reflection-point group of reflection points of the electromagnetic waves reflected by an object that is present on the travel route. An image acquiring unit acquires an image of the travel route using a camera. A reflection point correcting unit corrects the reflection-point group by removing an erroneous reflection point that is determined to be highly likely not to be a reflection point of a roadside object from the reflection-point group through image processing of the image. A shape recognizing unit recognizes a shape of the roadside object using the corrected reflection-point group.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority fromearlier Japanese Patent Application No. 2017-238208, filed Dec. 13,2017, the description of which is incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to a technology for recognizing aroadside object that is present on a travel route on which a vehicletravels, the roadside object being used for driving control of the ownvehicle.

Related Art

In automatic driving of a vehicle, a shape (travel road shape) of atravel road on which an own vehicle travels is recognized, and drivingcontrol is performed such that the own vehicle travels along therecognized travel road shape. For the travel road shape to berecognized, the shapes of a plurality of objects that can be used todetermine the travel road shape are recognized through use of varioustypes of onboard sensors, such as cameras and radars. For example, suchobjects include travel road boundary lines (lane markers) such as whitelines and roadside objects such as guardrails.

Japanese Patent Publication No. 5402983 describes a technology forrecognizing a roadside object using a radar. A plurality of reflectionpoints are obtained through measurement performed by the radar.Therefore, the shape of the roadside object can be recognized as aresult of the plurality of reflection points being successivelyconnected. However, the reflection points from an object other than theroadside object are present as noise points among the reflection points.Therefore, a process for excluding such noise points is desired.Japanese Patent Publication No. 5402983 discloses a technology in whichthe reflection points that are present between a preceding vehiclerecognized by the radar and an own vehicle are excluded as the noisepoints.

In the case in Japanese Patent Publication No. 5402983, the noise pointscannot be excluded when the preceding vehicle is not detected by theradar. For recognition of the shape of a roadside object, a technologyfor removing noise points of a radar under various circumstances isdesired.

SUMMARY

An exemplary embodiment provides a roadside object recognition apparatusthat recognizes a roadside object that is present on a travel route onwhich a vehicle travels, for use in driving control of the own vehicle.The roadside object recognition apparatus includes: a reflection pointacquiring unit that acquires, using a radar that emits electromagneticwaves, a reflection-point group of reflection points of theelectromagnetic waves reflected by an object that is present on thetravel route; an image acquiring unit that acquires an image of thetravel route using a camera; a reflection point correcting unit thatcorrects the reflection-point group by removing an erroneous reflectionpoint that is determined to be highly likely not to be a reflectionpoint of the roadside object from the reflection-point group throughimage processing of the image; and a shape recognizing unit thatrecognizes a shape of the roadside object using the correctedreflection-point group.

As a result of the roadside object recognition apparatus, the erroneousreflection point that is highly likely not to be the reflection point ofthe roadside object is removed from the reflection-point group throughimage processing of the image of the travel route. Therefore, noisepoints can be appropriately removed. The likelihood of the roadsideobject being erroneously recognized can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a block diagram of a configuration of an automatic drivingcontrol system according to a first embodiment;

FIG. 2 is an explanatory diagram of an example of a plurality of objectsassociated with a travel road shape according to the first embodiment;

FIG. 3 is an explanatory diagram of an example of an image captured by acamera;

FIG. 4 is a flowchart of a roadside object recognition process;

FIG. 5 is an explanatory diagram of a setting example of a travel roadarea using travel road boundary lines:

FIG. 6 is an explanatory diagram of a setting example of a travel roadarea using an other vehicle locus:

FIG. 7 is an explanatory diagram of a setting example of a travel roadarea using a road edge;

FIG. 8 is an explanatory diagram of a setting example of a travel roadarea using the travel road boundary line and the other vehicle locus:

FIG. 9 is an explanatory diagram of a process for recognizing a roadsideobject from a corrected reflection-point group:

FIG. 10 is an explanatory diagram of an example of a method for settingthe travel road area using a recognized overhead object:

FIG. 11 is an explanatory diagram of another example of the method forsetting the travel road area using a recognized overhead object:

FIG. 12 is an explanatory diagram of a road including a temporaryboundary line; and

FIG. 13 is an explanatory diagram of a method for excluding reflectionpoints using the temporary boundary line.

DESCRIPTION OF THE EMBODIMENTS A. First Embodiment

As shown in FIG. 1, a vehicle 50 according to a first embodimentincludes an automatic driving control system 100 that corresponds to avehicle control system. The automatic driving control system 100includes an automatic driving electronic control unit (ECU) 200, avehicle control unit 300, a front detection apparatus 410, a reardetection apparatus 420, and an assistance information acquiring unit500. In the present description, the vehicle 50 is also referred to asan “own vehicle 50.”

The automatic driving ECU 200 is a circuit that includes a centralprocessing unit (CPU) and a memory. The automatic driving ECU 200actualizes the respective functions of an automatic driving control unit210 and a state recognizing unit 220 by running a computer program thatis stored in a non-volatile storage medium. A part of the functions ofthe automatic driving ECU 200 may be implemented by a hardware circuit.

The state recognizing unit 220 recognizes the driving states of the ownvehicle 50 and an other vehicle 60, and the surrounding environmentusing various types of information and detection values that areprovided by the front detection apparatus 410, the rear detectionapparatus 420, the assistance information acquiring unit 500, andgeneral sensors 340.

According to the present embodiment, the state recognizing unit 220includes a reflection point acquiring unit 222, an image acquiring unit224, a reflection point correcting unit 226, a shape recognizing unit228, and a travel road shape calculating unit 230. Of the foregoing, thereflection point acquiring unit 222, the image acquiring unit 224, thereflection point correcting unit 226, and the shape recognizing unit 228as a whole configure a roadside object recognition apparatus thatrecognizes a roadside object that is present on a travel route on whichthe own vehicle 50 travels. In other words, according to the presentembodiment, the automatic driving ECU 200 functions as the roadsideobject recognition apparatus.

The reflection point acquiring unit 222 acquires a reflection-pointgroup using a radar 414 of the front detection apparatus 410. Thereflection-point group includes reflection points of electromagneticwaves (e.g., radio waves or lights) reflected by an object that ispresent on the travel route. The image acquiring unit 224 acquires animage of the travel route using a camera 412.

The reflection point correcting unit 226 corrects the reflection-pointgroup acquired by the reflection point acquiring unit 222 by removingthe reflection points (erroneous reflection points, noise points)determined to be highly likely not to be the reflection points (actualreflection points) of a roadside object from the reflection-point group,through image processing performed on the image captured by the camera412. Details of this correction will be further described hereafter. Thereflection point correcting unit 226 also provides a function forrecognizing boundary lines and other objects using the images capturedby the camera 412 and the results of measurement by the radar 414.

The shape recognizing unit 228 recognizes the shape of the roadsideobject using the reflection-point group corrected by the reflectionpoint correcting unit 226. More specifically, the shape recognizing unit228 calculates a two-dimensional shape of the roadside object, such as aguardrail. Here, the “two-dimensional shape” refers to a shape thatappears in a planar view of the own vehicle 50 and the travel routethereof.

The travel road shape calculating unit 230 calculates a shape (travelroad shape) of the travel road on which the own vehicle 50 travels usingthe shape of the roadside object recognized by the shape recognizingunit 228. However, for calculation of the travel road shape, therecognition results regarding travel road boundary lines, such as whitelines, are preferably also used in addition to the roadside object.

The vehicle control unit 300 is a section that performs various types ofcontrol for driving the vehicle 50. The vehicle control unit 300 is usedfor both automatic driving and manual driving. The vehicle control unit300 includes a drive unit control apparatus 310, a brake controlapparatus 320, a steering angle control apparatus 330, and the generalsensors 340.

The drive unit control apparatus 310 provides a function for controllinga drive unit (not shown) that drives the wheels of the vehicle 50. Atleast one of a plurality of motors including an internal combustionengine and an electric motor can be used as the drive unit for thewheels.

The brake control apparatus 320 performs brake control of the vehicle50. For example, the brake control apparatus 320 is configured as anelectronically controlled brake system (ECB).

The steering angle control apparatus 330 controls a steering angle ofthe wheels of the vehicle 50. The “steering angle” refers to an averagesteering angle of the two front wheels of the vehicle 50. For example,the steering angle control apparatus 330 is configured as an electricpower steering system (EPS).

The general sensors 340 include a vehicle speed sensor 342, a steeringangle sensor 344, and a yaw rate sensor 346. The general sensors 340 aregeneral sensors that are required for driving the vehicle 50. Thegeneral sensors 340 include sensors that are used in either of automaticdriving and manual driving.

The front detection apparatus 410 acquires information related tovarious types of objects, such as objects and road facilities (such astraffic lanes, intersections, and traffic lights), that are presentahead of the own vehicle 50. The front detection apparatus 410 usesonboard sensors to acquire the information. According to the presentembodiment, the front detection apparatus 410 includes the camera 412and the radar 414.

A monocular camera or a stereo camera can be used as the camera 412. Inaddition, the camera 412 is preferably a color camera to enabledifferentiation between the colors of the objects (such asdifferentiation between a white travel road boundary line and a yellowtravel road boundary line). Various types of radars that emitelectromagnetic waves (e.g., radio waves or lights), such as a lightdetection and ranging (LIDAR) apparatus that emits light or a radar(such as a millimeter-wave radar) that emits radio waves, can be used asthe radar 414.

The rear detection apparatus 420 acquires information related to varioustypes of objects, such as objects and road facilities, that are presentto the rear of the own vehicle 50. The rear detection apparatus 420 canalso be configured to include onboard sensors similar to those of thefront detection apparatus 410.

The assistance information acquiring unit 500 acquires various types ofassistance information for automatic driving. The assistance informationacquiring unit 500 includes a global navigation satellite system (GNSS)receiver 510, a navigation apparatus 520, and a wireless communicationapparatus 530.

The GNSS receiver 510 determines a current position (longitude andlatitude) of the own vehicle 50 based on navigation signals receivedfrom satellites configuring the GNSS. The navigation apparatus 520provides a function for determining a predicted travel route forautomatic driving based on a destination and the own vehicle positiondetected by the GNSS receiver 510. In addition to the GNSS receiver 510,other sensors, such as a gyro sensor, may be used to determine andcorrect the predicted travel route.

The wireless communication apparatus 530 is capable of exchanging stateinformation related to the state of the own vehicle 50 and the state ofthe surrounding environment through wireless communication with anintelligent transport system 70. The wireless communication apparatus530 is also capable of exchanging the state information throughinter-vehicle communication with the other vehicle 60, and road-vehiclecommunication with a roadside transceiver that is set in a roadfacility.

The assistance information acquiring unit 500 may acquire some pieces ofinformation related to the driving state of the own vehicle 50 using thestate information acquired through such wireless communication. Thevarious types of assistance information acquired by the assistanceinformation acquiring unit 500 are transmitted to the automatic drivingECU 200.

In the present description, “automatic driving” refers to driving inwhich all of drive unit control, brake control, and steering anglecontrol are automatically performed without the driver performingdriving operations. Therefore, in automatic driving, an operation stateof the drive unit, an operation state of the brake mechanism, and thesteering angle of the wheels are automatically determined. “Manualdriving” refers to driving in which the driver performs an operation(stepping on an accelerator pedal) for drive unit control, an operation(stepping on a brake pedal) for brake control, and an operation(rotation of a steering wheel) for steering angle control.

The automatic driving control unit 210 performs control for automaticdriving of the own vehicle 50 using the various states recognized by thestate recognizing unit 220. Specifically, the automatic driving controlunit 210 transmits a drive indicator value to the drive unit controlapparatus 310. The drive indicator value indicates the operation stateof the drive unit (engine and motor).

The automatic driving control unit 210 also transmits a brake indicatorvalue to the brake control apparatus 320. The brake indicator valueindicates the operation state of the brake mechanism. The automaticdriving control unit 210 also transmits a steering angle indicator valueto the steering angle control apparatus 330. The steering angleindicator value indicates the steering angle of the wheels. The controlapparatuses 310, 320, and 330 perform control of the respectivemechanisms to be controlled based on the provided indicator values. Forexample, the various functions of the automatic driving control unit 210can be implemented through artificial intelligence using machinelearning such as deep learning.

The automatic driving control system 100 has numerous electronicapparatuses including the automatic driving ECU 200. The plurality ofelectronic apparatuses are connected to each other via an onboardnetwork such as a controller area network (CAN).

As shown in FIG. 2, when the own vehicle 50 travels along a travel routeSDR, the state recognizing unit 220 can recognize a plurality of objectsthat are associated with the travel road shape. Here, a left edge LE anda right edge RE of the road, travel road boundary lines WL1, WL2, andWL3, and a roadside object RSO are shown as the objects that can berecognized by the state recognizing unit 220. The two travel roadboundary lines WL1 and WL3 are solid white lines. The travel roadboundary line WL2 in the center is a broken white line. For example, theroadside object RSO is a guardrail. These objects can be recognizedthrough use of images captured by the camera 412 and detection resultsfrom the radar 414.

A preceding other vehicle 60 may be driving ahead of the own vehicle 50.The presence and travel locus (travel trajectory) of the other vehicle60 such as this can also be recognized through use of the imagescaptured by the camera 412 and the detection results from the radar 414.A false boundary line FWL that is easily erroneously recognized as atravel road boundary line is present on the road surface near the centertravel road boundary line WL2.

Hereafter, a process for recognizing the roadside object RSO as theobject used to calculate the shape (travel road shape) of the travelroad on which the own vehicle 50 travels will be described. In additionto the guardrail, other objects that are present on the shoulder of theroad, such as a curbstone or a row of poles on the shoulder of the road,can be recognized as the roadside object.

As shown in FIG. 3, the image captured by the camera 412 includes theleft edge LE and the right edge RE of the road, the travel road boundarylines WL1, WL2, and WL3, and the roadside object RSO shown in FIG. 2.The image further includes an overhead object (upper object) UOB that ispresent above the own vehicle 50. In this example, the overhead objectUOB is a road sign. However, the image may include an elevatedstructure, such as an overpass or a pedestrian bridge, as the overheadobject UOB.

Here, “above the own vehicle 50” means that the position of the overheadobject UOB in a vertical direction is higher than the own vehicle 50 anddoes not mean that the overhead object UOB is required to be presentdirectly above the own vehicle 50. The radar 414 is capable of detectingthe reflection points of the electromagnetic waves on the roadsideobject RSO and the overhead object UOB. Therefore, the reflection pointacquiring unit 222 may acquire a reflection-point group that includesnot only the reflection points of the roadside object RSO, but also thereflection points of the overhead object UOB.

The reflection points of the overhead object UOB become noise when theroadside object RSO is being recognized. Therefore, the reflectionpoints of the overhead object UOB should be removed from thereflection-point group. According to the first embodiment, a travel roadarea that includes the travel road on which the own vehicle 50 travelsis set in the image captured by the camera 412. The reflection pointspresent within the travel road area are removed from thereflection-point group. The details of this process will be describedhereafter.

As shown in FIG. 4, in the process for recognizing the roadside objectRSO, first, at step S110, the reflection point acquiring unit 222acquires the reflection-point group from the detection results of theradar 414. As described above, the reflection-point group may includenot only the reflection points of the roadside object RSO, but also thereflection points of the overhead object UOB.

At step S120, the image acquiring unit 224 acquires an image of thetravel route using the camera 412. For example, the image is an imagesuch as that shown in FIG. 3, described above.

At step S130, the reflection point correcting unit 226 corrects thereflection-point group by removing the reflection points that are highlylikely not to be the reflection points of the roadside object RSOthrough image processing of the image captured by the camera 412. Thepositions of the reflection points acquired through measurement by theradar 414 are converted to positions in the image captured by the camera412 by a predetermined coordinate transformation matrix.

According to the first embodiment, in the process at step S130, thetravel road area including the travel road on which the own vehicle 50travels is set by image processing. The reflection points present in thetravel road area are determined to be highly likely not to be thereflection points of the roadside object RSO and are removed from thereflection-point group. For example, this process can be performedthrough use of at least one of three methods, described below.

<Method 1 (FIG. 5)> A travel road area RLA1 of the own vehicle 50 is setwith reference to the travel road boundary lines WL1 to WL3. Reflectionpoints RP8 and RP9 that are present in the travel road area RLA1 arethen removed from the reflection-point group.

<Method 2 (FIG. 6)> A travel road area RLA2 of the own vehicle 50 is setwith reference to the locus of a preceding other vehicle 61. Thereflection points RP8 and RP9 that are present in the travel road areaRLA2 are then removed from the reflection-point group.

<Method 3 (FIG. 7)> A travel road area RLA3 of the own vehicle 50 is setwith reference to the road edge RE. The reflection points RP8 and RP9that are present in the travel road area RLA3 are then removed from thereflection-point group.

Specific examples of the above-described methods 1 to 3 in a case inwhich the roadside object RSO to be recognized is present on a rightside of the own vehicle 50 will be described below. In a case in whichthe roadside object RSO is present on a left side of the own vehicle 50,the description below is made similarly applicable by “left” and “right”in the description below being reversed.

In the example in FIG. 5, the travel road boundary lines WL1 to WL3 arerecognized through image processing of the image captured by the camera412. In this case, an area on the left side of the travel road boundaryline WL1 that is present furthest to the right among the travel roadboundary lines recognized on the right side of the own vehicle 50 is setas the travel road area RLA1. The travel road area RLA1 is shaded withdots. At this time, the reflection point correcting unit 226 removes thereflection points RP8 and RP9 that are present in the travel road areaRLA1 from the reflection-point group. As a result, the reflection-pointgroup of the reflection points RP1 to RP7 of the roadside object RSO canbe accurately recognized.

FIG. 5 shows a two-dimensional coordinate system in which avehicle-width direction is an X axis and a direction perpendicular tothe X axis is a Y axis, with a reference position of the own vehicle 50as a point of origin. The vehicle-width direction X is also referred toas a “lateral direction.” The position of the reflection point isprescribed by an XY-coordinate value. In addition, the travel roadboundary lines WL1 to WL3 are recognized as two-dimensional shapes onthe XY coordinate system. This similarly applies to the other-vehicletravel locus and the road edge described hereafter.

In the example in FIG. 6, at least one of preceding other vehicles 61and 62 are recognized through image processing on the image captured bythe camera 412. In this case, an area on the left side of a right-edgeposition of the locus of the other vehicle 61 that is present furthestto the right among the other vehicles recognized on the right side ofthe own vehicle 50 is set as the travel road area RLA2.

Here, “the other vehicles 61 recognized on the right side of the ownvehicle 50” refers to a vehicle of which a left-right (lengthwise)center line of the vehicle is present on the right side of theleft-right center line of the own vehicle 50. In addition, “the locus ofthe other vehicle 61” refers to a locus of a right edge OVE of the othervehicle 61 that travels, and a locus that is recognized from a pluralityof images that are captured in time-series.

When the travel road area RLA2 is set using the locus of the othervehicle 61, the range of the travel road area RLA2 along an advancingdirection of the own vehicle 50 is preferably set so as to extend to aposition at the rear end of the other vehicle 61. The reflection pointcorrecting unit 226 removes the reflection points RP8 and RP9 that arepresent in the travel road area RLA2 from the reflection-point group. Asa result, the reflection-point group of the reflection points RP1 to RP7of the roadside object RSO can be accurately recognized.

In the example in FIG. 7, the road edges LE and RE are recognizedthrough image processing of the image captured by the camera 412. Inthis case, an area on the left side of the road edge RE recognized onthe right side of the own vehicle 50 is set as the travel road areaRLA3. The reflection point correcting unit 226 removes the reflectionpoints RP8 and RP9 that are present in the travel road area RLA3 fromthe reflection-point group. As a result, the reflection-point group ofthe reflection points RP1 to RP7 of the roadside object RSO can beaccurately recognized.

In the example in FIG. 8, the travel road boundary line WL1 that is thereference object used in FIG. 5 (method 1) and the locus of the othervehicle 61 that is the reference object used in FIG. 6 (method 2) arerecognized. In cases in which a plurality of reference objects that canbe used to set the travel road area are present in this manner, thetravel road area is preferably set using the reference object with whichthe widest travel road area can be obtained, among the plurality ofreference objects.

That is, in the example in FIG. 8, of the area (RLA1 in FIG. 5) on theleft side of the travel road boundary line WL1 present furthest to theright among the travel road boundary lines recognized on the right sideof the own vehicle 50 and the area (RLA2 in FIG. 6) on the left side ofthe locus of the other vehicle 61 present furthest to the right amongthe other vehicles 61 recognized on the right side of the own vehicle50, the wider area is set as the travel road area RLA4. In this case aswell, the reflection point correcting unit 226 removes the reflectionpoints RP8 and RP9 that are present in the travel road area RLA4 fromthe reflection-point group. As a result, the reflection-point group ofthe reflection points RP1 to RP7 of the roadside object RSO can beaccurately recognized.

The travel road area corresponding to each reference object isdetermined based on predetermined rules for each reference object. Inthe example in FIG. 8, instead of the widest area among the plurality oftravel road areas RLA1 and RLA2 set using a plurality of referenceobjects being selected as the travel road area RLA4, a sum area of theareas RLA1 and RLA2 may be set as the travel road area to be used forremoval of the reflection points.

In FIG. 5 to FIG. 8, described above, the travel road area that includesthe travel road on which the own vehicle 50 travels is set through imageprocessing of the image captured by the camera 412. The reflectionpoints present in the travel road area are determined to be highlylikely not to be the reflection points of the roadside object RSO andare removed from the reflection-point group. However, the reflectionpoints determined to be highly likely not to be the reflection points ofthe roadside object RSO may be selected and removed through a methodother than the method in which the travel road area is set.

For example, as can be understood from FIG. 3, in the image captured bythe camera 412, the roadside object RSO is often an object that extendsfrom the left side or the right side of the screen towards a vanishingpoint in the image. Therefore, the reflection points that are unlikelyto be the reflection points of such an object may be removed from thereflection-point group.

As shown in FIG. 9, when the reflection-point group is corrected as aresult of the unnecessary reflection points RP8 and RP9 being removedfrom the reflection-point group RP1 to RP9, at step S140 in FIG. 4, theshape recognizing unit 228 recognizes the shape of the roadside objectRSO using the corrected reflection-point group RP1 to RP7.

Specifically, the shape recognizing unit 228 recognizes thetwo-dimensional shape of the roadside object RSO by successivelyconnecting the reflection points in the corrected reflection-point groupRP1 to RP7. A technology for recognizing the shape of the roadsideobject RSO from the reflection-point group is known. Therefore, adetailed description thereof is omitted herein.

At step S150, the travel road shape calculating unit 230 calculates thetravel road shape using the recognized roadside object RSO.Specifically, the travel road shape calculating unit 230 calculates theshape (travel road shape) of the travel road on which the own vehicle 50travels from the shapes of the roadside object RSO and other objects(such as the travel road boundary lines WL1 to WL3). The automaticdriving control unit 210 performs automatic driving of the own vehicle50 using the travel road shape calculated in this manner.

As described above, according to the first embodiment, thereflection-point group is corrected by the reflection points determinedto be highly likely not to be the reflection points of the roadsideobject RSO being removed from the reflection-point group through imageprocessing of the image captured by the camera 412. The shape of theroadside object RSO is then recognized through use of the correctedreflection-point group.

That is, according to the first embodiment, the reflection points thatare highly likely not to be the reflection points of the roadside objectRSO are removed from the reflection-point group through use of theresults of image processing performed on the image of the travel route.Therefore, the noise points can be appropriately removed. The likelihoodof the shape of the roadside object RSO being erroneously recognized canbe reduced.

B. Second Embodiment

According to a second embodiment, when an object in an image captured bythe camera 412 is recognized as being the overhead object UOB (FIG. 3)through image processing of the image, a process shown in FIG. 10,described below, is performed in addition to the above-describedprocesses (FIG. 5 to FIG. 8) according to the first embodiment.

For example, the method for recognizing the overhead object UOB of theown vehicle 50 in an image includes pattern matching between the objectin the image and numerous template images of overhead objects registeredin advance. Alternatively, an object in the image can be recognizedthrough use of artificial intelligence to which machine learning hasbeen applied, and the object can be recognized as an overhead objectshould the object be present above the vanishing point in the image.

Moreover, when the GNSS signal cannot be detected, the likelihood of anoverhead structure, such as an overpass or the ceiling of a tunnel,being present is high. Therefore, a determination that an overheadstructure is present may be made. However, in the latter case, asdescribed hereafter, an area that is beyond a distance (such as a valueranging from 50 meters to 60 meters) set in advance is preferably set asan overhead object area UA1.

As shown in FIG. 10, when an object in the image is recognized as beingthe overhead object UOB of the own vehicle 50, an overhead object areaUA1 in which the overhead object UOB is assumed to be present is set.The reflection points RPa, RP8, and RP9 that are present in the overheadobject area UA1 are then removed from the reflection-point group. FIG.10 also shows the travel road area RLA1 that has been set in the processin FIG. 5. Among the three reflection points RPa, RP8, and RP9 removedfrom the reflection-point group in the process in FIG. 10, thereflection point RPa is outside of the travel road area RLA1. Therefore,the reflection point RPa cannot be removed in the process in FIG. 5.

For example, the reflection point RPa corresponds to the reflection ofelectromagnetic waves from a column of the overhead object UOB in theimage shown in FIG. 3. In such cases as well, should the overhead objectarea UA1 in which the overhead object UOB is assumed to be present beset, and the reflection points RPa, RP8, and RP9 present in the overheadobject area UA1 be removed from the reflection-point group, the shape ofthe roadside object RSO can be more accurately recognized.

The overhead object area UA1 in which the overhead object UOB is assumedto be present can be set through various methods. According to thesecond embodiment, the overhead object area UA1 is set as an area beyonda position at which the overhead object UOB is calculated or estimatedto be present. For example, when the camera 412 is a stereo camera, thedistance to the overhead object UOB from the own vehicle 50 can becalculated from the image captured by the stereo camera. The areaextending beyond the calculated distance can be set as the overheadobject area UA1.

In addition, when the camera 412 is a single-lens camera, the distanceto the overhead object UOB can be estimated based on the coordinates ofthe overhead object UOB in the image captured by the camera 412, thecoordinates of the reflection points of the overhead object UOB measuredby the radar 414, and the distance to the reflection points. The areaextending beyond this distance can be set as the overhead object areaUA1. Alternatively, in cases in which the position at which the overheadobject UOB is present cannot be calculated or estimated, an area beyonda distance (such as a value ranging from 50 meters to 60 meters) set inadvance may be set as the overhead object area UA1.

As described above, according to the second embodiment, when theoverhead object UOB (such as a destination guidance sign or an elevatedroad) is recognized as being present above the travel road on which theown vehicle 50 travels, the overhead object area UA1 in which theoverhead object UOB is assumed to be present is set. The reflectionpoints present in the overhead object area UA1 are then removed from thereflection-point group. As a result, the likelihood of the overheadobject UOB being erroneously recognized as the roadside object RSO canbe reduced.

C. Third Embodiment

According to a third embodiment, when an object in an image captured bythe camera 412 is recognized as being the overhead object UOB (FIG. 3)through image processing the image, a process shown in FIG. 11,described below, is performed in addition to the above-describedprocesses (FIG. 5 to FIG. 8) according to the first embodiment. In amanner similar to the process in FIG. 10, the process in FIG. 11,described hereafter, is a process in which an overhead object area UA2in which the overhead object UOB is assumed to be present is set. Thereflection points RPa, RP8, and RP9 present in the overhead object areaUA2 are then removed from the reflection-point group. The thirdembodiment differs from the second embodiment in terms of the settingmethod of the overhead object area UA2.

As shown in FIG. 11, according to the third embodiment, the overheadobject area UA2 is set as an area within a predetermined distance fromthe position at which the overhead object UOB is calculated or estimatedto be present. For example, when the camera 412 is a stereo camera, theposition of the overhead object UOB can be calculated from the imagecaptured by the stereo camera. The area within a predetermined distance(such as 2 meters) from the calculated position can then be set as theoverhead object area UA2.

In addition, when the camera 412 is a single-lens camera, athree-dimensional position of the overhead object UOB can be estimatedbased on the coordinates of the overhead object UOB in the imagecaptured by the camera 412, the coordinates of the reflection points ofthe overhead object UOB measured by the radar 414, and the distance tothe reflection points. The area within a predetermined distance from theestimated position can then be set as the overhead object area UA2.According to the third embodiment as well, effects similar to thoseaccording to the second embodiment can be achieved.

D. Fourth Embodiment

In an example shown in FIG. 12, the travel route SDR includes atemporary boundary line TLM. The temporary boundary line TLM is aboundary line that indicates that the section of road is a temporarytravel section. For example, the temporary boundary line TLM is drawn onthe road surface as a composite line including a white line and a yellowline.

In addition, a row of poles PL is often set within the area of thetemporary boundary line TLM. When the reflection point correcting unit226 recognizes the temporary boundary line TLM, the recognition can beperformed through use of other features (such as the left side being asolid white line, the lane width being narrow, or a vertically alignededge-point group [a point group of the row of poles PL or the like]being continuously present), in addition to the feature that is theboundary line being the composite line including the white line and theyellow line. According to the fourth embodiment, a process that isperformed when the row of poles PL is recognized as the roadside objectwill be described.

In the example shown in FIG. 13, the reflection-point group obtained bythe radar 414 includes reflection points RP11 to RP18 that correspond tothe row of poles PL in FIG. 12, and reflection points RP* that areobtained from another roadside object. The reflection point correctingunit 226 determines whether or not the temporary boundary line TLM isincluded in the image captured by the camera 412. When determined thatthe temporary boundary line TLM is included in the image, the reflectionpoint correcting unit 226 sets an area RLA7 other than a temporaryboundary line area TLA that includes the temporary boundary line TLM.

For example, the temporary boundary line area TLA can be set as an areathat circumscribes the temporary boundary line TLM. Alternatively, thetemporary boundary line area TLA may be set as an area obtained by amargin of a predetermined width (such as 40 centimeters to 60centimeters) being provided on the outer side of the area circumscribingthe temporary boundary line TLM. The reflection point correcting unit226 removes the reflection points RP* that are present in the area RLA7from the reflection-point group.

As described above, when the temporary boundary line TLM is included inthe image captured by the camera 412, should the reflection points RP*present in the area RLA7 other than the temporary boundary line TLM beremoved from the reflection-point group, the roadside object such as therow of poles PL included in the area of the temporary boundary line TLMcan be accurately recognized.

In particular, this process is greatly effective in terms of enablingthe roadside object included in the area of the temporary boundary lineTLM to be accurately recognized in a location in which significant noiseis present among the reflection points, such as inside a tunnel.Correction of the reflection-point group according to the fourthembodiment is also a type of process for removing the reflection pointsdetermined to be highly likely not to be the reflection points of aroadside object from the reflection-point group through image processingof the image.

The present disclosure is not limited to the above-describedembodiments. Various modes are possible without departing from thespirit of the present disclosure.

What is claimed is:
 1. A roadside object recognition apparatus thatrecognizes a roadside object (RSO, PL) that is present on a travel routeon which an own vehicle travels, the roadside object being used fordriving control of the own vehicle, the roadside object recognitionapparatus comprising: a reflection point acquiring unit that acquires,using a radar that emits electromagnetic waves, a reflection-point groupof reflection points of the electromagnetic waves reflected by an objectthat is present on the travel route; an image acquiring unit thatacquires an image of the travel route using a camera; a reflection pointcorrecting unit that corrects the reflection-point group by removing anerroneous reflection point that is determined to be highly likely not tobe a reflection point of the roadside object from the reflection-pointgroup through image processing of the image; and a shape recognizingunit that recognizes a shape of the roadside object using the correctedreflection-point group.
 2. The roadside object recognition apparatusaccording to claim 1, wherein: the reflection point correcting unit setsa travel road area that includes a travel road on which the own vehicletravels in the image and removes the erroneous reflection point presentin the travel road area from the reflection-point group.
 3. The roadsideobject recognition apparatus according to claim 2, wherein: when aplurality of reference objects that can be used for setting the travelroad area are recognized, the reflection point correcting unit sets thetravel road area using the reference object with which a widest travelroad area can be obtained, among the plurality of reference objects. 4.The roadside object recognition apparatus according to claim 2, wherein:when a plurality of reference objects that can be used for setting thetravel road area are recognized, the reflection point correcting unitsets a sum area of a plurality of areas set using the plurality ofreference objects as the travel road area.
 5. The roadside objectrecognition apparatus according to claim 2, wherein: when an overheadobject that is recognized as being present above the travel road onwhich the own vehicle travels is included in the image, the reflectionpoint correcting unit sets an overhead object area in which the overheadobject is assumed to be present and removes the erroneous reflectionpoint present in the overhead object area from the reflection-pointgroup.
 6. The roadside object recognition apparatus according to claim3, wherein: when an overhead object that is recognized as being presentabove the travel road on which the own vehicle travels is included inthe image, the reflection point correcting unit sets an overhead objectarea in which the overhead object is assumed to be present and removesthe erroneous reflection point present in the overhead object area fromthe reflection-point group.
 7. The roadside object recognition apparatusaccording to claim 4, wherein: when an overhead object that isrecognized as being present above the travel road on which the ownvehicle travels is included in the image, the reflection pointcorrecting unit sets an overhead object area in which the overheadobject is assumed to be present and removes the erroneous reflectionpoint present in the overhead object area from the reflection-pointgroup.
 8. The roadside object recognition apparatus according to claim1, wherein: when a temporary boundary line that is a boundary lineindicating a temporary travel section is included in the image, thereflection point correcting unit removes the erroneous reflection pointpresent in an area other than a temporary boundary line area includingthe temporary boundary line from the reflection-point group.
 9. Theroadside object recognition apparatus according to claim 2, wherein:when a temporary boundary line that is a boundary line indicating atemporary travel section is included in the image, the reflection pointcorrecting unit removes the erroneous reflection point present in anarea other than a temporary boundary line area including the temporaryboundary line from the reflection-point group.
 10. The roadside objectrecognition apparatus according to claim 3, wherein: when a temporaryboundary line that is a boundary line indicating a temporary travelsection is included in the image, the reflection point correcting unitremoves the erroneous reflection point present in an area other than atemporary boundary line area including the temporary boundary line fromthe reflection-point group.
 11. The roadside object recognitionapparatus according to claim 4, wherein: when a temporary boundary linethat is a boundary line indicating a temporary travel section isincluded in the image, the reflection point correcting unit removes theerroneous reflection point present in an area other than a temporaryboundary line area including the temporary boundary line from thereflection-point group.
 12. The roadside object recognition apparatusaccording to claim 5, wherein: when a temporary boundary line that is aboundary line indicating a temporary travel section is included in theimage, the reflection point correcting unit removes the erroneousreflection point present in an area other than a temporary boundary linearea including the temporary boundary line from the reflection-pointgroup.
 13. A vehicle control system comprising: a roadside objectrecognition apparatus that recognizes a roadside object that is presenton a travel route on which an own vehicle travels; and a controlapparatus that performs driving control of the own vehicle based on theroadside object recognized by the roadside object recognition apparatus,the roadside object recognition apparatus comprising: a reflection pointacquiring unit that acquires, using a radar that emits electromagneticwaves, a reflection-point group of reflection points of theelectromagnetic waves reflected by an object that is present on thetravel route; an image acquiring unit that acquires an image of thetravel route using a camera; a reflection point correcting unit thatcorrects the reflection-point group by removing an erroneous reflectionpoint that is determined to be highly likely not to be a reflectionpoint of the roadside object from the reflection-point group throughimage processing of the image; and a shape recognizing unit thatrecognizes a shape of the roadside object using the correctedreflection-point group.
 14. A roadside object recognition method forrecognizing a roadside object that is present on a travel route on whichan own vehicle travels, the roadside object being used for drivingcontrol of the own vehicle, the roadside object recognition methodcomprising: acquiring, using a radar that emits electromagnetic waves, areflection-point group of reflection points of the electromagnetic wavesreflected by an object that is present on the travel route; acquiring animage of the travel route using a camera; correcting thereflection-point group by removing an erroneous reflection point that isdetermined to be highly likely not to be a reflection point of theroadside object from the reflection-point group through image processingof the image; and recognizing a shape of the roadside object using thecorrected reflection-point group.